Enhanced electronic transport properties in complementary binary discotic liquid crystal systems

Kreouzis, Theo; Scott, K.; Donovan, Kevin J.; Boden, N.; Bushby, Richard J.; Lozman, Owen R.; Liu, Q

doi:10.1016/s0301-0104(00)00323-2

Cited by 59 publications

(46 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For instance a large lateral slide of a molecule leads to a relatively small charge transfer integral and consequently a low mobility. The lower mobility values of the order of 0.001 cm 2 V Ϫ1 s Ϫ1 or less, 12 as found from TOF measurements on alkoxy-substituted triphenylenes, are most likely due to such effects.…”

Section: B Alkoxy-and Alkylthio-substituted Triphenylenementioning

confidence: 91%

“…1.͒ Of particular relevance to their possible use in electronic device applications are charge carrier mobility measurements. Experimental mobility values have been obtained from time-of-flight ͑TOF͒ measurements, [5][6][7][8][9][10][11][12][13] pulseradiolysis time-resolved microwave conductivity ͑PR-TRMC͒ measurements 14 -20 and frequency dependent AC conductivity measurements on doped samples. [21][22][23][24] The conductivity in triphenylene derivatives is mainly due to transport of positive charges ͑holes͒ and for the liquid crystalline phase mobility values in the range 10 Ϫ3 -10 Ϫ1 cm 2 V Ϫ1 s…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Senthilkumar

Grozema

Bickelhaupt

et al. 2003

The Journal of Chemical Physics

410

417

View full text Add to dashboard Cite

Values of charge transfer integrals, spatial overlap integrals and site energies involved in transport of positive charges along columnar stacked triphenylene derivatives are provided. These parameters were calculated directly as the matrix elements of the Kohn-Sham Hamiltonian, defined in terms of the molecular orbitals on individual triphenylene molecules. This was realized by exploiting the unique feature of the Amsterdam density functional theory program that allows one to use molecular orbitals on individual molecules as a basis set in calculations on a system composed of two or more molecules. The charge transfer integrals obtained in this way differ significantly from values estimated from the energy splitting between the highest occupied molecular orbitals in a dimer. The difference is due to the nonzero spatial overlap between the molecular orbitals on adjacent molecules. Calculations were performed on unsubstituted and methoxy-or methylthio-substituted triphenylenes. Charge transfer integrals and site energies were computed as a function of the twist angle, stacking distance and lateral slide distance between adjacent molecules. The variation of the charge transfer integrals and site energies with these conformational degrees of freedom provide a qualitative explanation of the similarities and differences between the experimental charge carrier mobilities in different phases of alkoxy-and alkylthio-substituted triphenylenes. The data obtained from the present work can be used as input in quantitative studies of charge transport in columnar stacked triphenylene derivatives.

show abstract

Section: B Alkoxy-and Alkylthio-substituted Triphenylenementioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Senthilkumar

Grozema

Bickelhaupt

et al. 2003

The Journal of Chemical Physics

410

417

View full text Add to dashboard Cite

show abstract

“…In the materials investigated in this work the conductivity has been attributed to transport of holes. 20,21 From frequency-dependent conductivity measurements in the range 28 -38 GHz the dose-normalized endof-pulse ͑EOP͒ conductivity ⌬ EOP /D is obtained. The onedimensional ͑1D͒ hole mobility along the columnar direction, 1D , is derived from the relationship 1D ϭ3(⌬ EOP /D)(E p /W p ), where E p is the average electronhole pair formation energy and W p is the probability that these ion pairs survive to the end of the 3-MeV electron pulse.…”

Section: Methodsmentioning

confidence: 99%

“…24 From TOF experiments on two of these mixtures it was concluded that the charge-carrier mobility in the hexagonal columnar (Col h ) mesophase of the mixtures is up to three orders of magnitude higher than that of the HAT molecules separately. 20 This high mobility was shown to persist at room temperature in the glassy phase of the mixtures.…”

Section: Introductionmentioning

confidence: 93%

“…Of particular relevance to their possible use in electronic device applications are charge-carrier mobility measurements, of which quite a number have been published. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The two main methods that have been used for this purpose are time-of-flight ͑TOF͒ and pulse-radiolysis time-resolved microwave conductivity ͑PR-TRMC͒, 22,23 which are both nonperturbative, time-resolved techniques.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Charge-carrier mobilities in binary mixtures of discotic triphenylene derivatives as a function of temperature

et al. 2002

View full text Add to dashboard Cite

The pulse-radiolysis time-resolved microwave conductivity technique was used to study charge transport in three binary mixtures of triphenylene derivatives and in three of these components separately. In the liquidcrystalline mesophase the hole mobilities in the mixtures are found to be an order of magnitude higher than those in the separate components. This is partly due to the more stable columnar structure in the mixtures and partly due to efficient ''alloy band formation.'' In the crystalline phase the mobility in the mixtures is only a few times lower than that of the separate components. The ionization energies of the components as measured by cyclic voltammetry are up to ϳ0.5 eV apart. It turns out that this energy difference is easily compensated by the relatively large charge-transfer integrals for hole transport in the binary mixtures, which was obtained from ab initio Hartree Fock calculations. The mobilities estimated theoretically for ordered systems largely exceed the experimental values. This is most likely due to structural disorder along the columns in the material. Theoretical estimations of the hole mobility suggest that mobilities in excess of 1 cm 2 /V s could be attainable in well-ordered crystalline triphenylene samples.

show abstract

Photopolymerization and Molecular Orientational Order of the Discotic Nematic Phase in 2,3,6,7,10,11-Hexakis(4-(8-acryloyloxyoctyloxy)benzoyloxy)triphenylene

Ukon

Sugino

Watanabe³

et al. 2002

Macromol. Mater. Eng.

View full text Add to dashboard Cite

Enhanced electronic transport properties in complementary binary discotic liquid crystal systems

Cited by 59 publications

References 11 publications

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Charge-carrier mobilities in binary mixtures of discotic triphenylene derivatives as a function of temperature

Photopolymerization and Molecular Orientational Order of the Discotic Nematic Phase in 2,3,6,7,10,11-Hexakis(4-(8-acryloyloxyoctyloxy)benzoyloxy)triphenylene

Contact Info

Product

Resources

About